Amplifying device



July 9, 1935- R DAVIES 2,U@7,946

AMPLIFYING DEVICE Filed Aug. 25, 1950 2 Sheets-Shae? l INVENTOR W01 WQM ATTORNEY July 9, 1935.

i H. R. DAVIES AMPLIFYING DEVICE Filed Aug 23, 1930 2 Sheets-Sheet 2 INVENTOB %2/// Ram was ATTORNEY Patented July 9, 1935 UNITED STATES PATENT OFFICE 7 Henry R. Davies, Valley Cottage, N. Y; assignor to Sirian Lamp Company, Newark, N. J., a cor-,

poration of Delaware Application August 23, 193a1se ial M47145? .6Claims. (o1. '50-- -27.5)

This invention relates to an amplifying device based on the principles involved in the combined metal-gas energy radiator.

In the well known type of amplifier for electromagnetic wave signals use in made of direct elec tron emission from an electron emitter in an evacuated tube, the emission being from the emitterto a plate or anode at a different potential, and the electron stream being controlled by the grid r m interposed between the emitter cathode and the i the conductor and the contained gas act as a source of energy emission.

Another object of the invention is to provide an improved amplifying device which will increase the density of current movement so that the capacity of the tube may be increased.

Another object is to provide an amplifying device in which it isnot-essential that the high voltage be maintained across the space intermediate the anode and cathode, thus simplifying the operation of the amplifier over tubes built according toprior practice. i v

Various other objects pertaining to details of construction and operative steps, as well as to other features of the invention, will appear on consideration of the following description in conjunction with the accompanying drawings, in which: r r Fig. lis a side elevation showing the radiating elements including the cathode, anode, and control element;

Fig. 2 is an elevation of the device in Fig. 1 from a position at rightangles thereto;

Fig. 3 is a plan view of the cathode shown in Figs. 1 and 2; i r

Fig. 4 is a view of a modified type of amplifier;

Fig. 5 is a section through the operative ele ments of the device of Fig. 3.

.In a co-pending application Serial No. 459,048, filed June 3, 1930, there is described a type of energy radiator in which a conducting element is coated with an electronemitting material, and placed in acontainer containing an ionizable gas at a predetermined pressure and therein subjectedto a potential sufficient to activate the coating and ionize the gaseous atmosphere immediately surrounding the coating to form a combined metallic and gaseous conductor of intense energy. a

In accordance with said application, a filament of appropriate resistance, such, for example, as

150 ohrns, is coated with various alkaline oxides such asthe oxides of barium, strontium, calcium or other materials which have been found to emit electrons densely when heated. The base filament is tungstenor tantalum wire, although other 7 5 metal conductors may be used. It is not necessary ordinarily that the base material be highly refractory, as the operating temperatures may be relatively low, in many cases not being above that of low red heat, H

yThefilament is prefer bly coiled and coated with materialsas above mentioned, which may be initially in the proportions of 40 grams of barium carbonate, 40 grams of calcium carbonate, 8 grams of barium nitrate with a binder of sufficient nitrocellulose dissolved in amyl acetate to hold the coating on the, wire, and the filament isthen mounted on a stem support and sealed in the bulb of the envelope.

The exhaust, pump is then connected to the bulb and an oven lowered thereupon to raise the temperature of the bulb and contents to about 400 C.,,or to ashigh a temperature as the envelope will stand without softening. Simultaneously electric current is passed through the filament which is heated to red heat of approximately 600 C. The heat and exhausting process is continued. until there is no fluorescence when the high tension current is directed against the wall of the bulb, or in other words, until there is practically no more gas insideof the bulb. A vacuum of about one-half of a micron is an approximate limiting .value. r g

The current is then increased through the filament so tha't the temperature thereof is slowly raised until it is about 300 degrees, or abright red color, the exhaust operation being continued until the newly emitted gases are removed. The oven is then raised from the bulb and the filament heated to about 1200 C,., the pumping being continued until a high vacuum of one-half micron is againobtained.

Y The pump is then. shut ofif, the current turned off,and about one-half mm. of neon gas admitted to the bulb. The filament current is then turned on and gradually increased until a diffused glow completely fills the bulb. When the discharge is uniform throughout the bulb, it usually takes less than ten minutes, the so-called activating process; for the filament coating is completed. Should white discharge spots appear on the filament or support rods, it is an indication that the gases or vapors within the bulb have not been completely removed, and the bulb is again exhausted and the whole processor activation re peated. When the activating process is finally complete, the filament temperature is raised for a short interval to about 1400" C., and the pumping operation is again resumed to remove any undesirable gases which may have been thrown off during the activation process.

The filament circuit is then disconnected and the pump turned off and the appropriate amount of gas admitted to the bulb. In one form of my invention I utilize neon and argon gases in the relative amounts of 50 mm. of neon gas, and 150 mm. of argon. Other monatomic gases such as krypton, helium, or metal vapors such as those of mercury, caesium, and rubidium may also be used. The bulb is then sealed off and a small quantity of magnesium flashed to absorb additional impurities, thus completing the process.

In accordance with the principles of the above radiator, I insert in a bulb I0, which may be preferably transparent, a stem I I which is sealed to the bulb in and in which are mounted the supports [2, l3, M, 15, It, and IT. "The supports 1'2 and I? form the terminals of the cathode I8. This cathode is a series of separated V-shaped, oval or elliptical coils 19, each of which consists of closely wound tungsten or tantalum wire coated with electron emitting material such as was described hereinabove in connection with the energy radiator. The standards 13 and 16 are connected by a conductor 21 which passes through the coils IQ of the cathode t8, and to this wire 2! at points approximately in the plane of the coils [9 are attached, as by welding or other means, metal loops 2!. The standards I! and 15 are also connected by a metal conducting rod or wire 23, and this wire passes through the loops 22, and consequently through the loops I! also. The wire 23 constitutes the anode of the amplifier.

Standards 12 and H pass through the stem H and constitute lead-in wires 24 and 5 for the energizing circuit for the cathode. Standard 13 is extended into the lead-in wire 2% which is connected to the control potential of the amplifier. Standard I5 is connected to lead-in wire 21, and this in turn is connected to the appropriate plate potential, if such is found to 'be desirable, in the particular circuit arrangement contemplated.

The various structural elements as above described being appropriately positioned within the tube, the activation process hereinabove mentioned with reference to the energy emitter are carried on and subsequently inert gases or vapors are introduced, such as a mixture of neon and argon in the proportionate parts of 50 mm. of neon and 150 mm. of argon. Other combinations of these gases might be used, including the use, either singly or in combination, of krypton, helium, and the vapors of mercury or caesium. Mercury vapor may be introduced into the bulb by placing therein a button of magnesium holding the same, or as mercuric chloride, or as an alloy, and caesium also might be introduced in the usual way as by electromagnetic heating of a button of the metal previously positioned within the envelope prior to sealing. Various other monatomic gases could 'be utilized.

In the operation of the amplifying device the cathode I8 is appropriately heated by the passage of an electric current therethrough. At the operating potential 'a layer of highly activated ionized gases forms about the turns of the coils 19 which, because of the elliptical or oval contour or the coil with the apex a at base as shown, the activated gases tend to bridge the closely adjacent segments (1-1) and a-c, as illustrated in Fig. 2, so that the activated gaseous area includes both the anode Z3 and the control grid 2|. Should a varying voltage be now applied to the control grid 2| it will cause an alternate contraction and expansion of the activated gaseous layer, according to whether the voltage of the control grid is positive or negative and in accordance with the movement of the maximum of voltage in the control grid in either phase. The movement of the gas layer is most pronounced at the points a where the loops [9 have closely adjacent segments and a slight change of voltage of the control grid produces a relative- 1y large movement of the activated gas boundary. Thus the conditions for amplification are met and in this manner the gas current flow, including the cathode and anode and the output circuit of the amplifying unit, is modified and controlled and electromagnetic fluctuations introduced into the control circuit from an input circuit are transmitted to the output circuit.

In the modification of Fig. l, instead of the plurality of adjacent coils l9 forming the cathode I utilize a plurality of parallel conductors 36, the ends of which are connected by connecting rods Si and 32. These conductors Eli are bent each in the shape of a V, the vertex 33 of each of the conductors being attached to but insulated from the standard 34 mounted in the stem 35- of the bulb 36. The rods 3| and 32 likewise are attached through standards 3! and to the stem 35, and appropriate lead-in wires 39 and 40 connect the conductors 3| and 32 to a source of current supply.

In this modification of the invention the control element or grid takes the form of the main rod '4'! having extending arms 12 and 43 which may be duplicated as often as found desirable, these arms forming a V of an angle approximately the same as that formed by the conductors 30 of the cathode, as illustrated in Fig. 5 of the drawings. The anode M takes the shape of a section of a. cylindrical shell vertically positioned adjacent the control grid, as illustrated in Fig. 5. The control grid through the standard 4| is mounted on the stem '35 of the bulb 36 and the control po-- tential circuit is also connected to the rod. The anode or plate 44 is supported in the stem by standards 45 and '66 and standard 46 has connection to the lead-in wire 17 by which the circuit through the anode and cathode is completed. The operation of the modification of the invention as shown in Fig. 4 is identical to that of the device in Fig. 1.

In either form of the invention the amount of potential which should be inserted in the anode circuit is, of course, dependent upon the particular demands to be placed on the amplifier. Because of the high conductivity of the gaseous path intermediate the cathode and anode a relatively small potential, compared with the high potential used in the ordinary vacuum tube, is usually found to be sufiicient.

While I have described the device hereinabove as an amplifier, it is, of course apparent that the characteristics thereof are such as to permit use of the device as a conductor for electrical signals.

Various gases have been mentioned as satisfactory for the device hereinabove described, these gases being generally identified as the monatomic or inert gases. They may further be defined as gases which, when used in the device described, have a breakdown potential along the axis of the conductor less than the potential necessary to raise the electron emitting coating to electron emitting temperature. Use has also been described of a coating of electron emitting material. This coating may be applied externally or internally to the conducting coil, or it may be in the form of a rod of material inserted within the coil, and hence the use of the term coating should not impart a. limitation to the meaning of the claims, but should be understood to include these various means of placing an electron emitting coating in juxtaposition to the conductor to be heated thereby.

Various modifications other than those hereinabove described may, of course, be made by those versed in this particular art, and hence I do not desire to be limited by the modifications described or other than'in accordance with the claims hereinafter made. I

I desire to claim as my invention:

I 1. In an amplifying device the combination of an envelope, a support positioned within said envelope and attached thereto, a pair of standards mounted on said support, a conductor in the form of parallel coils connected between said standards, a second pair of standards, a-conductor connected between said second pair of standards, a plurality of conducting loops attached to said second named conductor so that a single loop is Within a coil, the plane of the loop and its enclosing coil being approximately the same, a third pair of standards mounted on said support, a third conductor connected between said standards, said third conductor passing between said loops and said coils, and an atmosphere of inert ionizable gases Within said envelope.

' 2. In an amplifying device the combination of an envelope, a support positioned within said envelope and attached thereto, a pair of standards mounted on said support, a conductor in the ,form of parallel coils connected between said standards, a second pair of standards, a conductor connected between said second pair of standards, a plurality of conducting loops attached to said second named conductor so that a single loop is within a cell, the plane of the loop and its enclosing cell being approximately the same, a third pair of standards mounted on said support, a third conductor connected between said standards, said third conductor passing between said loops and said coils, a coating of electron emitting material on said coils, and an atmosphere of inert ionizable gases within said envelope.

3. In an amplifying device the combination of an envelope, a support positioned Within said envelope and attached thereto, a pair of standards mounted on said support, a conductor in the form of parallel coils connected between said standards, a second pair of standards, a conductor connected between said second pair of standards, a plurality of conducting loops attached to said second named conductor so that a single loop is within a coil, the plane of the loop and its enclosing coil being approximately the same, a third pair of standards mounted on said support, a third conductor connected between said standards, said third conductor passing betweensaid loops and said coils, and an atmosphere of inert ionizable gases within said envelope, said coils having relatively closely positioned adjacent sec tions at the points where the second and third conductors pass therethrough.

4. In an amplifying device the combination of an envelope, a support positioned withinsaid envelope and attached thereto, a pair of standards mounted on said support, a conductor in the form of parallel coils connected between said standards, a second pair of standards, a conductor connected between said second pair of standards, a plurality of conducting loops attached tosaid second named conductor so that a single loop is within a coil, the plane of the loop and its enclosing coil being approximately the same, a third pair of standards mounted on said support, a third conductor connected between said standards, said third conductor passing between said loops and said coils, and an atmosphere of inert ionizable gases within said envelope, said coils having portions of their boundaries in the form of a V with closely adjacent diverging segments.

5. In an amplifying device the combination of an envelope, a support positioned therein, a metal conductor, conducting standards supporting the conductor within said envelope, said conductor having portions thereof formed with closely adjacent segments, an anode within said envelope, a control element within said envelope, conducting standards supporting said anode and control element within the envelope with said control element and anode lying within the area bounded by said closely adjacent sections of the conductor, and an atmosphere of ionizable gases Within said envelope and immersing said conductor, anode, and control element.

6. In an amplifying device the combination of an envelope, a support positioned therein, a metal conductor, conducting standards supporting the conductor within said envelope, said conductor having portions thereof formed with closely adwhich surrounds the anode and in turn is surrounded by a portion of the conductor.

HENRY R. DAVIES. 

